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SDLC Interview Questions and Answers

Updated Jan 08, 2020

What is SDLC and what does SDLC stand for?

SDLC stands for Software Development Life Cycle which is the process used by the software developers to design, develop, maintain, test and deploy software.

The cycle describes the process flow of the development of the software to meet user expectations properly while adhering to the development guidelines.

What is the first step of the system development life cycle (SDLC)?

The first step of the SDLC is requirement analysis of the software. Based on customer requirements and sales data, the developers chalk out the basic approach needed for the software project. A technical, economic, social and operational feasibility study is carried out in this phase. The possible risks associated with the software project are also identified here.

What are the different phases of SDLC?

The different phases of SDLC are:

  1. Requirement analysis and planning
  2. Definition
  3. Design
  4. Development
  5. Testing
  6. Deployment and maintenance

What is the design phase in SDLC?

In the design phase, the basic design approach to be followed for developing the software is proposed based on the Software Requirement Specification (SRS). The data flow representation and architectural modules are defined here. The details are documented in a DDS (Design Document Specification).

What Is the Coding Phase in SDLC?

In this phase, the actual code for the software is written here based on the information gathered from the DDS (Design Document Specification) and the SRS (Software Requirement Specification). Based on the type of software product, the programming language is chosen like Python, Java or C#.

The budget, time, robustness and risks associated with the project are analyzed here.

What is the Testing Phase in SDLC?

Before deployment of the software, it is tested for problems. The SDLC stages where the defects and bugs are reported are fixed here. The entire software is retested until it meets the quality specifications mentioned in the SRS (Software Requirement Specification).

It is analyzed whether the software works according to customer requirements and meets their demands.

What Is the Maintenance Phase in SDLC?

After the deployment of the software, the product needs to be maintained to meet the market demands. In the maintenance stage, the software is monitored to measure its stability, flexibility, user-friendliness, and performance.

Based on the analysis report and customer feedbacks, the software is further upgraded and tweaked using patches. New updates to the software are also released by the development team.

What Is the Deployment Phase in SDLC?

After the software product is tested and it passes through every level of the testing phase, it is formally launched in the deployment phase. It may be released as a demo or prototype for getting user reviews, upon which the product will be improved further.

The formalities like handing over the ownership of the product, deployment preparation and closing the phase are carried out in this stage.

What is testing Phase?

Before deployment of the software, it is tested for problems. The SDLC stages where the defects and bugs are reported are fixed here. The entire software is retested until it meets the quality specifications mentioned in the SRS (Software Requirement Specification).

It is analyzed whether the software works according to customer requirements and meets their demands.

What is the implementation phase in the SDLC?

The implementation phase consists of the coding, testing, integration, and installation of the software product. The product is coded according to the DDS (Design Document Specification).

Test cases are used to analyze if the software works according to the user’s needs. After the errors and bugs are fixed, the product is then installed to check its performance.

What are SDLC models?       

The different SDLC models are Iterative, Waterfall, Agile, V-Shaped and Spiral. Starting from the basic Waterfall model the other models gave evolved based on the product type, the target audience and the platforms where they have to be executed.

Which SDLC model is best?           

There is no model that can be considered as the best in case of software development. However, the Agile model is currently the most popular and widely used by software firms.

In this model after every development stage, the user is able to see whether the product meets their requirements. The risks are reduced this way as continuous alterations are done based on user feedback.

Difference between SDLC and STLC?

The difference between SDLC and STLC are given below:

SDLC STLC
It is the Software Development Life Cycle used by the developers to design, test, develop and deploy a software product. It is the software testing life cycle that consists of the various processes to test the software product in the Testing phase of the SDLC.
The requirements are gathered from market and sales data, which is analyzed by the development team. The testing team analyses the requirements for testing the product by SRS (Software Requirement Specification) document.
Based on the SRS, the developers write the code for the software in the development phase. A test architect or test lead writes the code for test cases and identify the testing points to use these cases.
After deployment, the development teams release update or patches to improve the functionality of the product. After deployment, the testers release updated test plans and automation scripts for the product.

What does SDLC mean in networking protocol?

In networking, SDLC stands for Synchronous Data Link Control that is a protocol used for communication. It is developed by IBM and is a layer 2 protocol.

What is SDLC waterfall model?

The Waterfall model is the earliest of the SDLC models also known as Linear-Sequential Life Cycle Model. In this model, each stage has to be completed before the initialization of the next step. The sequential flow of the model is responsible for its name.

Which SDLC phases can be Automated?

The most common SDLC stage that is automated is the Testing phase. The automation can be done successfully in the STLC (Software Testing Life Cycle).

What is prototyping in SDLC?

Prototyping in SDLC is a process through a software prototype is developed depicting the core functionality of the software product but does not show the actual details or logic. It is actually a working model of the software that allows the users to understand whether the product meets their needs.

Based on the analysis, the developer can further enhance and update the software. This process reduces the costs and time taken for development as the problems are fixed before implementation. The prototyping types are rapid, incremental, evolutionary and extreme.

What is the V model in SDLC?

The V model in SDLC is also known as the Verification and Validation model. It is an expansion of the waterfall model and is based on the associated test stages for the developmental stages.

The verification phases include requirement analysis, product design, architecture design, and module design. The validation phases include unit, system, integration and acceptance testing. Here, a stage is initialized after the previous stage is completed.

How do DD LC and SDLC work parallel?

The DDLC (Documentation Development Life Cycle) is basically a developmental life cycle used by the technical documenters for preparing the documentation of the software. The life cycle is followed alongside the SDLC, as the testers and developers work parallel to create the software.

The documentation needs input and feedback from the different stages in the SDLC, therefore the DDLC has similar stages:

  • Analyzing the requirements
  • Designing the outline of the technical documentation
  • Development of the documentation
  • Review
  • Finalize the documentation content
  • Publish the documentation

What is the spiral model in SDLC?   

The Spiral model is a combination of the iterative and the waterfall model. Here, the product is developed and improved after each iteration of the model. This model is used for complicated and expensive projects.

This spiral model has 4 phases:

  • Identification of the requirements – The system requirements of the product is obtained here by the communication between the system analyst and the end user.
  • Designing – The physical, architectural, module and the product designs are made here for the software.
  • Construction – This is the phase where the POC (Proof of Concept) is developed for receiving the user reviews on the product. Later on, a working model called Build is developed.
  • Risk analysis – The risks associated with the product are identified here.     


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